epoll: Split handling of TCP timerfds into its own handler function

tcp_sock_handler() actually handles several different types of fd events.
This includes timerfds that aren't sockets at all.  The handling of these
has essentially nothing in common with the other cases.  So, give the
TCP timers there own epoll_type value and dispatch directly to their
handler.  This also means we can remove the timer field from tcp_epoll_ref,
the information it encoded is now implicit in the epoll_type value.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

4 files changed, 12 insertions, 14 deletions

diff --git a/passt.c b/passt.c
index 2d674bf..a700e41 100644
--- a/passt.c
+++ b/passt.c
@@ -57,6 +57,7 @@ char pkt_buf[PKT_BUF_BYTES]	__attribute__ ((aligned(PAGE_SIZE)));
 
 char *epoll_type_str[EPOLL_TYPE_MAX + 1] = {
 	[EPOLL_TYPE_TCP]	= "TCP socket",
+	[EPOLL_TYPE_TCP_TIMER]	= "TCP timer",
 	[EPOLL_TYPE_UDP]	= "UDP socket",
 	[EPOLL_TYPE_ICMP]	= "ICMP socket",
 	[EPOLL_TYPE_ICMPV6]	= "ICMPv6 socket",
@@ -324,6 +325,9 @@ loop:
 			if (!c.no_tcp)
 				tcp_sock_handler(&c, ref, eventmask, &now);
 			break;
+		case EPOLL_TYPE_TCP_TIMER:
+			tcp_timer_handler(&c, ref);
+			break;
 		case EPOLL_TYPE_UDP:
 			udp_sock_handler(&c, ref, eventmask, &now);
 			break;
diff --git a/passt.h b/passt.h
index 8878a11..fc1efdb 100644
--- a/passt.h
+++ b/passt.h
@@ -47,8 +47,10 @@ union epoll_ref;
 enum epoll_type {
 	/* Special value to indicate an invalid type */
 	EPOLL_TYPE_NONE = 0,
-	/* Sockets and timerfds for TCP handling */
+	/* TCP sockets */
 	EPOLL_TYPE_TCP,
+	/* timerfds used for TCP timers */
+	EPOLL_TYPE_TCP_TIMER,
 	/* UDP sockets */
 	EPOLL_TYPE_UDP,
 	/* IPv4 ICMP sockets */
diff --git a/tcp.c b/tcp.c
index 18b781a..98761a2 100644
--- a/tcp.c
+++ b/tcp.c
@@ -663,9 +663,8 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 	conn->c.in_epoll = true;
 
 	if (conn->timer != -1) {
-		union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP,
+		union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP_TIMER,
 					  .fd = conn->sock,
-					  .tcp.timer = 1,
 					  .tcp.index = CONN_IDX(conn) };
 		struct epoll_event ev_t = { .data.u64 = ref_t.u64,
 					    .events = EPOLLIN | EPOLLET };
@@ -692,9 +691,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 		return;
 
 	if (conn->timer == -1) {
-		union epoll_ref ref = { .type = EPOLL_TYPE_TCP,
+		union epoll_ref ref = { .type = EPOLL_TYPE_TCP_TIMER,
 					.fd = conn->sock,
-					.tcp.timer = 1,
 					.tcp.index = CONN_IDX(conn) };
 		struct epoll_event ev = { .data.u64 = ref.u64,
 					  .events = EPOLLIN | EPOLLET };
@@ -2813,12 +2811,12 @@ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref ref,
  *
  * #syscalls timerfd_gettime
  */
-static void tcp_timer_handler(struct ctx *c, union epoll_ref ref)
+void tcp_timer_handler(struct ctx *c, union epoll_ref ref)
 {
 	struct tcp_tap_conn *conn = conn_at_idx(ref.tcp.index);
 	struct itimerspec check_armed = { { 0 }, { 0 } };
 
-	if (!conn)
+	if (c->no_tcp || !conn)
 		return;
 
 	/* We don't reset timers on ~ACK_FROM_TAP_DUE, ~ACK_TO_TAP_DUE. If the
@@ -2935,11 +2933,6 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
 {
 	union tcp_conn *conn;
 
-	if (ref.tcp.timer) {
-		tcp_timer_handler(c, ref);
-		return;
-	}
-
 	if (ref.tcp.listen) {
 		tcp_conn_from_sock(c, ref, now);
 		return;
diff --git a/tcp.h b/tcp.h
index 5499127..8eb7782 100644
--- a/tcp.h
+++ b/tcp.h
@@ -13,6 +13,7 @@
 
 struct ctx;
 
+void tcp_timer_handler(struct ctx *c, union epoll_ref ref);
 void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
 		      const struct timespec *now);
 int tcp_tap_handler(struct ctx *c, int af, const void *addr,
@@ -31,7 +32,6 @@ void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
  * union tcp_epoll_ref - epoll reference portion for TCP connections
  * @listen:		Set if this file descriptor is a listening socket
  * @outbound:		Listening socket maps to outbound, spliced connection
- * @timer:		Reference is a timerfd descriptor for connection
  * @index:		Index of connection in table, or port for bound sockets
  * @u32:		Opaque u32 value of reference
  */
@@ -39,7 +39,6 @@ union tcp_epoll_ref {
 	struct {
 		uint32_t	listen:1,
 				outbound:1,
-				timer:1,
 				index:20;
 	};
 	uint32_t u32;